1. Field of the Invention
The present invention relates to a method for forming fine patterns of a semiconductor device, and more specifically, to a method for forming fine patterns of a semiconductor device which overcomes resolution limits of exposure equipment.
2. Description of the Related Art
Lithography resolution (R) for a lithography process is determined by a relationship of a wavelength (λ) of a light source used in exposure equipment and a numerical aperture (NA) as expressed in the following equation:R=k1×λ/NA 
In the equation, k1 indicates a process factor and has a physical (optical) limit, e.g., k1=0.25. Conventional resolution enhancement techniques cannot surpass this limit.
ArF exposure equipment with a 0.93 numerical aperture has recently been developed. With additional technical advances in photoresist material and masking, it is now possible to form a 60 nm pattern. However, forming a pattern of less than 60 nm is difficult because a pitch is reached where light that includes image information cannot penetrate.
Therefore, forming a line and space pattern of less than 60 nm requires ArF immersion lithography.